The present invention concerns new prostacyclin derivatives, processes for their preparation and their use as medicines.
Prostacyclin (PGI.sub.2) is one of the main factors in blood platelet aggregation. It acts in a dilating manner on various blood vessels (Science 196, 1072) and therefore can be considered as a means for lowering blood pressure. PGI.sub.2, however, lacks the stability required for a medicine. Thus its half-life value at physiological pH values and at room temperature is only a few minutes. Prostacyclin derivatives are known from the German Offenlegungsschrift No. 27 53 244 and its U.S. equivalent U.S. Pat. No. 4,219,479 which have stability substantially increased by a cyano residue at the enolether double bond. However, even these compounds are in need of enhanced properties.